Fe─N₄ and Fe₇Co₃ Nanoalloy Dual‐Site Modulation by Skeleton Defect in N‐Doped Graphene Aerogel for Enhanced Bifunctional Oxygen Electrocatalyst in Zinc‐air Battery

Abstract The dual‐site electrocatalysts formed by metal single atoms combines with metal nanoparticles represent a promising strategy to enhance both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performance. Herein, defect engineering is applied to dual‐site ORR and OER electrocatalysts. Its design, synthesis, structural properties, and catalytic performance experimentally and theoretically are insightfully studied for the single‐atomic Fe─N₄ and the adjacent Fe₇Co₃ nanoalloy (FeCo_NA) as dual‐site loading on nitrogen‐doped graphene aerogel (Fe─N/FeCo@NGA). The high‐density dual‐sites, together with the good electronic conductivity of NGA, synergistically improve the electronic structure for superior electrocatalytic activity. The half‐wave potential of Fe─N/FeCo@NGA in ORR is 0.92 V and the overpotential of it in OER is 1.58 V. Corresponding all‐solid‐state Zn‐air battery demonstrates a peak power density of 147.6 mW cm⁻² and charge/discharge durability for over 140 h. Theoretical calculations reveal that the single‐atomic Fe‐N₄ and FeCo_NA dual‐site on the skeleton defect optimized NGA, further refine the local electronic structure, modulating the tensile force on the O─O bond in ^*OOH intermediate, leading to its spontaneous dissociation and facilitating a significantly reduced energy barrier. This work takes a promising shortcut in the application of defect engineering for the development of highly efficient dual‐site bifunctional oxygen electrocatalysts with single atoms.